Designing a lab is not trivial, particularly if you have no experience in doing it before. My new lab (day 2 of the move....) was perhaps the ideal circumstance: a new building is being constructed, and you have a very free hand in determining the layout, the facilities, and so forth. In any realistic process you never get everything you want (e.g., this building does not have a building-wide deionized water system; I can't have unlimited space; there are restrictions based on cost and feasibility). The challenge is to end up with functional space - laid out intelligently, so that work flows well and you don't find yourself fighting with the building or yourselves. Sometimes this is not simple. In my original lab space, for example, that floor of the building was never designed with vibration-sensitive work in mind. The need to position certain pieces of equipment on the vibrationally quiet parts of the floor strongly influenced lab layout, rather than basic experimental logic.
Lab design ranges from the Big Picture (e.g., I have a couple of optics tables, so I should probably have a separate area with independently controlled lighting; I want isolation transformers to keep my sensitive measurement electronics off the power lines used for my big pumps.) to a zillion little details (e.g., where should every single electrical outlet and ethernet port be positioned? What about emergency power? Gas lines? What fittings are going to be on the chilled water lines?). Nothing is ever perfect, and there are always minor glitches (e.g., mislabeled circuit breakers). You also want to design for the future. If you think you're eventually going to need a gizmo that requires chilled water or a certain amount of 480V current, it's better to plan ahead, cost permitting.... The situation is definitely more constrained if you're moving into pre-existing space, particularly in an older building. Like many aspects of being a professor, this is something that no one ever sits down and teaches you. Rather, you're left to figure it out, hopefully with the help of a professional.